content: /*
   * Copyright 2016-present David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.basetypes;
  
  import java.util.Objects;
  import java.util.concurrent.atomic.*;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.Flowable;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
  
  /**
   * Maps the success value of this Solo into a Publisher and
   * emits its signals.
   *
   * @param <T> the upstream value type
   * @param <R> the downstream value type
   */
  final class SoloFlatMapPublisher<T, R> extends Flowable<R> {
  
      final Solo<T> source;
  
      final Function<? super T, ? extends Publisher<? extends R>> mapper;
  
      SoloFlatMapPublisher(Solo<T> source, Function<? super T, ? extends Publisher<? extends R>> mapper) {
          this.source = source;
          this.mapper = mapper;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super R> s) {
          source.subscribe(new FlatMapPublisherSubscriber<T, R>(s, mapper));
      }
  
      static final class FlatMapPublisherSubscriber<T, R>
      extends AtomicReference<Subscription>
      implements Subscriber<T>, Subscription {
  
          private static final long serialVersionUID = -3958458353930920644L;
  
          final Subscriber<? super R> downstream;
  
          final InnerSubscriber requested;
  
          final Function<? super T, ? extends Publisher<? extends R>> mapper;
  
          Subscription upstream;
  
          FlatMapPublisherSubscriber(Subscriber<? super R> downstream, Function<? super T, ? extends Publisher<? extends R>> mapper) {
              this.downstream = downstream;
              this.mapper = mapper;
              this.requested = new InnerSubscriber(downstream);
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.upstream, s)) {
                  this.upstream = s;
  
                  downstream.onSubscribe(this);
  
                  s.request(Long.MAX_VALUE);
              }
          }
  
          @Override
          public void onNext(T t) {
              Publisher<? extends R> p;
  
              try {
                  p = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null Publisher");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  downstream.onError(ex);
                  return;
              }
  
              p.subscribe(requested);
          }
  
          @Override
          public void onError(Throwable t) {
              downstream.onError(t);
          }
  
          @Override
          public void onComplete() {
              // ignored
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
              SubscriptionHelper.cancel(this);
          }
  
          @Override
          public void request(long n) {
              SubscriptionHelper.deferredRequest(this, requested, n);
          }
  
          final class InnerSubscriber extends AtomicLong implements Subscriber<R> {
  
              private static final long serialVersionUID = 2003600104149898338L;
  
              final Subscriber<? super R> downstream;
  
              InnerSubscriber(Subscriber<? super R> downstream) {
                  this.downstream = downstream;
              }
  
              @Override
              public void onSubscribe(Subscription s) {
                  SubscriptionHelper.deferredSetOnce(FlatMapPublisherSubscriber.this, requested, s);
              }
  
              @Override
              public void onNext(R t) {
                  downstream.onNext(t);
              }
  
              @Override
              public void onError(Throwable t) {
                  downstream.onError(t);
              }
  
              @Override
              public void onComplete() {
                  downstream.onComplete();
              }
          }
      }
  }
  